Subversion Repositories z80soc

library IEEE;

use  IEEE.STD_LOGIC_1164.all;

use  IEEE.STD_LOGIC_ARITH.all;

use  IEEE.STD_LOGIC_UNSIGNED.all;

LIBRARY lpm;

USE lpm.lpm_components.ALL;

ENTITY Char_ROM IS

        PORT(   clock                                           : IN    STD_LOGIC;

                        character_address                       : IN    STD_LOGIC_VECTOR(7 DOWNTO 0);

                        font_row, font_col                      : IN    STD_LOGIC_VECTOR(2 DOWNTO 0);

                        rom_mux_output  : OUT   STD_LOGIC);

END Char_ROM;

ARCHITECTURE a OF Char_ROM IS

        SIGNAL  rom_data: STD_LOGIC_VECTOR(7 DOWNTO 0);

        SIGNAL  rom_address: STD_LOGIC_VECTOR(10 DOWNTO 0);

BEGIN

-- Small 8 by 8 Character Generator ROM for Video Display

-- Each character is 8 8-bits words of pixel data

 char_gen_rom: lpm_rom

      GENERIC MAP ( lpm_widthad => 11,

        lpm_numwords => 2048,

        lpm_outdata => "UNREGISTERED",

        lpm_address_control => "REGISTERED",

-- Reads in mif file for character generator font data

         lpm_file => "..\..\ROM\CHARROM.MIF",

         lpm_width => 8)

      PORT MAP ( inclock => clock, address => rom_address, q => rom_data);

rom_address <= character_address & font_row;

-- Mux to pick off correct rom data bit from 8-bit word

-- for on screen character generation

rom_mux_output <= rom_data ( (CONV_INTEGER(NOT font_col(2 downto 0))));

END a;